Method for producing polyisobutylphenols

ABSTRACT

Polyisobutenylphenols are prepared by alkylating an aromatic hydroxy compound with substantially monoethylenically unsaturated and substantially homopolymeric polyisobutenes in the presence of a Lewis acid alkylation catalyst by a process in which the polyisobutenes have a β double bond content of at least 35 mol %.

[0001] The present invention relates to a process for the preparation ofpolyisobutenylphenols by alkylating an aromatic hydroxy compound withsubstantially homopolymeric polyisobutenes in the presence of a Lewisacid alkylation catalyst.

[0002] It is known that aromatic hydroxy compounds can be alkylated withpolyolefins using acid catalysts for the preparation ofpolyalkenylphenols. This Friedel-Crafts alkylation does not as a rulelead to pure monoalkylation products since the alkylated products aremore reactive than the unsubstituted starting materials. A mixture ofdifferent mono-, di- and polyalkylation products is therefore generallyformed. Moreover, when high molecular weight alkylating agents are used,fragmentation reactions frequently occur both in the polyolefin and inthe alkylated product, so that as a rule a product mixture having acomplex composition is obtained.

[0003] Such mixtures are unsuitable for many industrial applications.Rather, products of defined composition are required, frequentlymonoalkylation products, it also being possible for the position of thealkylation to be relevant.

[0004] For example, polyisobutenylphenol is an important startingmaterial for the preparation of fuel detergents and is itself used as afuel additive. It is advantageous if the phenol is substantiallymonoalkylated and/or substituted in the para position.

[0005] In order to increase the proportion of monoalkylation products,the prior art proposes using the phenol component in a large excess. Thedisadvantage of this process measure is the necessary removal of largeamounts of unconverted phenols from the product mixture obtained.

[0006] GB-A-1 159 368 discloses the alkylation of phenol withmonoolefinic polymeric alkylating agents having molecular weights 40 offrom 700 to 300 000 using boron trifluoride phenolate.

[0007] U.S. Pat. No. 4,238,628 discloses a process for alkylatingbenzene, phenol and naphthol with polyolefins of monomers having atleast three carbon atoms, preferably polybutene, in the presence ofboron trifluoride as a catalyst. Before the alkylation reaction, theolefin polymer must be reacted with ethylene in order to obtain asubstantial ethylene termination. The yield of alkylphenol is only from44 to 64%.

[0008] U.S. Pat. No. 4,429,099 discloses the alkylation of phenol orsubstituted phenols with bis(polyisobutene)benzene ortris(polyisobutene)-benzene having molecular weights of from about 700to 50 000 and from about 1 000 to 75 000, respectively. The catalystsdisclosed are AlCl₃, AlBr₃, BF₃, BF₃O (C₂H₅)₂, TiCl₄, SnCl₄, AlC₂H₅Cl₂,FeCl₃, SbCl₅ and SbF₅. The polyisobutenes are vinylidene-terminated. Alarge excess of phenol is used, and long reaction times are required.

[0009] WO-A-94/14739 describes a process for the preparation ofpolyisobutenylhydroxy aromatics. In the process, a hydroxy aromaticcompound, e.g. phenol, catechol, resorcinol, hydroquinone or pyrogallol,is reacted with polyisobutene having a number average molecular weightof from 300 to 5 000 in the presence of an acidic alkylation catalyst.Here, it is necessary for the polyisobutene (PIB) to contain at least70% of terminal vinylidene units (α-olefin). The PIB:phenol ratio shouldvary within the limits of from 1:1.2 to 1:5. However, ratios of from 1:2to 1:3 are preferred and, in the examples disclosed, phenol is usedthroughout in a 100% excess (1:2). Without the evidence of a workingexample, it is asserted that the polyisobutenyl-phenols obtained wouldhave from 70 to 100% para-substitution, whereas polyisobutenephenolsprepared from conventional polyisobutene with a low α-olefin content(low vinylidene polyisobutenes=from 2 to 6% α-olefin content within themeaning of WO 94/14739) would have only from 0 to 40% para-substitution.This contradicts the experimental findings of EP-A-0 831 141. Example 1of this document, in terms of the nature and amount of the startingmaterials (especially the highly reactive polyisobutene employed),catalyst employed, the solvent and the reaction time and reactionduration, corresponds to example 1 of WO-A-94/14739. Nevertheless, onlya polyisobutenylphenol with 67% para-substitution is obtained. Here, thecommon teaching that highly reactive PIB leads to a high byproductfraction is confirmed.

[0010] J. Polym. Sci. A, 31, S. (1993), 1938 describes the use of SnCl₄as a catalyst. Here too, phenol is used in a large excess.

[0011] Kennedy, Guhaniyogi and Percec (Polym. Bull. 8, 563 (1970))describe the use of BF₃ diethyletherate as an alkylation catalyst, thePIB:phenol ratio being 1:2.5 or 1:1.7 (based in each case on thepolyisobutenyl terminal groups).

[0012] A common feature of the processes known to date for thealkylation of hydroxy aromatic compounds with polyolefins is that theyhave at least one and as a rule a plurality of the followingdisadvantages:

[0013] large excesses of phenol and/or amounts of catalyst are required,

[0014] the polyolefin used must contain a high proportion of α-olefinterminal units,

[0015] fragmentation reactions of the polyolefin or of the alkylatedproduct take place,

[0016] undesirable byproducts, such as polyalkylation products orproducts alkylated in an undesirable position, are also obtained,

[0017] the reaction times are long.

[0018] None of the abovementioned documents describes the use ofsubstantially homopolymeric polyisobutene having a high β-olefincontent.

[0019] It is an object of the present invention to provide an improvedprocess for alkylating aromatic hydroxy compounds. As far as possiblewith respect to the starting materials, preferably predominantlymonoalkylation products should result, it being possible to dispensewith a large excess of the phenol component. In the alkylation reaction,preferably substantially no fragmentation reactions of the polyalkene orof the alkylated product should take place. If possible productsalkylated preferably para to the OH function should result. Inparticular, the process should also be suitable for alkylatingpolyalkenes which have a relatively large proportion of non-α doublebonds.

[0020] We have found, surprisingly, that this object is achieved by analkylation process in which the reactivity is reduced by suitablemeasures. This can be effected on the side of the polyisobutene, byusing a polyisobutene having a β-olefin content of at least 35% (and anα-olefin content of at most 65%). In a preferred embodiment, a Lewisacid alkylation catalyst is additionally used in combination with anether as a cocatalyst.

[0021] The present invention relates to a process for the preparation ofpolyisobutenylphenols by alkylating an aromatic hydroxy compound withsubstantially monoethylenically unsaturated and substantiallyhomopolymeric polyisobutenes in the presence of a Lewis acid alkylationcatalyst, wherein the polyisobutenes have a β double bond content of atleast 35 mol %.

[0022] It was surprisingly found that polyisobutenes having a highcontent of β-olefin terminal units (e.g. more than 35 mol % or more than45 mol %), i.e. a low content of α-olefin terminal units (e.g. 65% orless), can generally be alkylated with good results in the presence of aLewis acid alkylation catalyst. Suitable Lewis acid alkylation catalystsare the ones mentioned below, in combination with a cocatalyst orwithout one.

[0023] The present invention therefore relates to a process for thepreparation of polyisobutenylphenols as described above, thepolyisobutenes having a non-α double bond content of at least 35 mol %.

[0024] In this process, the yield of desired monoalkylated product ishigh and fragmentation reactions and/or the formation of polyalkylatedproducts or products alkylated in an undesirable position arepredominantly avoided.

[0025] In the context of this invention a substantially homopolymericpolyisobutene is understood as meaning a polyisobutene which comprisesmore than 90% by weight of isobutene units. Suitable comonomers areC₃-C₆-alkenes, preferably n-butene. The preparation and structure of theoligoisobutenes/polyisobutenes are known to a person skilled in the art(e.g. Günther, Maenz, Stadermann in Ang. Makrom. Chem. 234, (1996) 71).Homopolyisobutenes having a number average molecular weight of fromabout 300 to 5 000 are particularly preferred. Particularly preferredmolecular weight ranges are from 400 to 3 000, in particular from 500 to2 500. The polydispersity PD of the polyolefins is preferably from 1.05to 3.0. However, it can if desired also be higher, for example greaterthan 5 or even greater than 12.

[0026] It is preferred to use polyisobutenes which if desired maycontain up to 10% of n-butene as an incorporated comonomer.Polyisobutenes of this kind are prepared, for example, frombutadiene-free C₄ cuts, which as a result of their production processgenerally include n-butene alongside isobutene. Particular preference isgiven to isobutene homopolymers.

[0027] Advantageously, the novel process is suitable for alkylatingpolyisobutenes which have a low proportion of α-double bonds. Thus, thenovel process also permits the use of industrially obtainablepolyisobutene mixtures for the alkylation.

[0028] Advantageously, the disadvantages known from the prior art and inparticular fragmentation reactions do not generally occur.

[0029] The novel process is suitable advantageously for alkylatingpolyisobutenes which contain substantially α-double bonds in addition toan inventively high fraction of β-double bonds. Surprisingly, betteryields of monoalkylated product and/or a lower tendency to the formationof polyalkylated products, or products alkylated at unwanted positions,are observed than when using polyisobutenes containing at least 70% ofα-double bonds. This effect occurs, surprisingly, especially when usingpolyisobutenes having β-double bonds and to a lesser extent when thedouble bonds are situated further toward the interior (γ-positionedbonds, etc.). Polyisobutenes which contain at least 70, particularlypreferably at least 80, especially at least 85, mol % of α- and/orβ-double bonds are preferably used for the alkylation, i.e., whichcontain at least 70 mol % of terminal methylvinylidene groups(—C(—CH₃)═CH₂) (=α-olefin) and/or dimethylvinyl groups (—CH═C(CH₃)₂)(=β-olefin).

[0030] Preferred polyisobutenes are reactive polyisobutenes which differfrom the low-reactivity polyisobutenes through the content of doublebonds in the α or β position. A particularly suitable reactivepolyisobutene is, for example, Glissopal® CE 5203 from BASF AG (42% ofβ-olefin, 58% of α-olefin, number average molecular weight M_(n)=1000).

[0031] In the context of this application, Lewis acid alkylationcatalysts are understood as meaning both individual acceptor atoms andacceptor atom-ligand complexes, molecules, etc., provided that they haveoverall (external) Lewis acid (electron acceptor) properties. Preferredcatalysts are the halides of boron, aluminum, tin or a transition metal,preferably titanium and iron. BF₃, SnCl₄, TiCl₄ and FeCl₃ areparticularly preferred.

[0032] In an advantageous embodiment, the alkylation catalysts (Lewisacids) are used together with at least one ether as a cocatalyst. Ethershaving a molecular weight of at least 102 g/mol are in general thepreferred embodiment. The molecular weight of the ethers is preferablyfrom 102 to 242 g/mol. BF₃ is easy to handle as a phenol complex.

[0033] Ethers suitable as cocatalysts and having a molecular weight ofless than 102 g/mol are, for example, dimethyl ether, ethyl methyl etherand diethyl ether. Ethers preferred as cocatalysts are selected fromsymmetrical and asymmetrical ethers which have two hydrocarbon radicalsof 6 to 16 carbon atoms in total. These hydrocarbon radicals may bealiphatic, cycloaliphatic or aromatic radicals. Cyclic ethers in whichthe ether group is part of the ring are also suitable. Di(C₃-C₈)alkylethers, such as di-n-propyl ether, diisopropyl ether, methyl tert-butylether and isopropyl tert-butyl ether, tetrahydrofuran,di(C₅-C₈)cycloalkyl ethers, such as dicyclohexyl ether and ethers havingat least one aromatic hydrocarbon radical, such as anisole, arepreferred.

[0034] The aromatic hydroxy compound used for the alkylation ispreferably selected from phenolic compounds having 1, 2 or 3 OH groups,which may have at least one further substituent. Preferred furthersubstituents are C₁-C₈-alkyl, in particular methyl and ethyl. Inparticular, compounds of the formula

[0035] where R¹ and R², independently of one another, are each hydrogen,OH or CH₃, are preferred. Phenol, the cresol isomers, catechol,resorcinol, pyrogallol, fluoroglucinol and the xylenol isomers areparticularly preferred. In particular, phenol, o-cresol and p-cresol areused. If desired, mixtures of the abovementioned compounds may also beused for the alkylation.

[0036] In the novel process, catalyst and cocatalyst are preferably usedin a molar ratio of from 1:10 to 10:1.

[0037] Advantageously, the novel process permits the substantiallyselective monoalkylation of aromatic hydroxy compounds without verylarge excess amounts of aromatic hydroxy compound having to be used, asdescribed in the prior art. Preferably, aromatic hydroxy compounds andpolyalkenes are used in a molar ratio of from 1.5:1 to 1:1, particularlypreferably from 1.2:1 to 1:1. Specifically it is possible to usearomatic hydroxy compounds and polyalkene in substantially equimolarratios, such as from 1.1:1 to 1:1, more especially from 1.05:1 to 1:1.An excess of the aromatic hydroxy compound of 100% or more, however, isof course also suitable. The novel process generally givespolyalkenylphenols which (if the starting material used permitspolyalkylations) have a degree of polyalkylation with the polyalkene ofnot more than 20, preferably not more than 10, in particular not morethan 5, mol %.

[0038] As a rule, from 1 to 30 mol %, based on the polyolefin, ofcatalyst or catalyst/cocatalyst complex are used. In specific cases,larger amounts such as 50 or 80 mol % can be used, for example toachieve higher rates of reaction. The complexes can have been producedbeforehand or are prepared in situ. The novel Lewis acids, as such or inan inert solvent, are combined with one or more ethers.

[0039] The novel process can advantageously be carried out as a rule inthe absence of a solvent. In some cases, however, the use of ahydrocarbon, such as n-alkane, or a mixture of said hydrocarbons as asolvent is advantageous. Owing to the low reactivity of thecatalyst/olefin complex alkyl aromatics or mixtures thereof may also beused. Aromatics, such as toluene, ethylbenzene, o-xylene, m-xylene,p-xylene, the isomeric trimethylbenzene or mixtures thereof (e.g. themixtures sold by Exxon Company as “aromatic 100” or “aromatic 150”), areparticularly advantageously used here, it being possible for furtherreaction stages to take place or the product being marketed.

[0040] The alkylation is preferably carried out at from −10° C. to +100°C. The exact reaction temperatures are dependent, inter alia, on thecatalyst used. A particularly preferred temperature range is from 15 to60° C., in particular from 15 to 40° C. The reaction is usually carriedout at atmospheric pressure but may also be carried out atsuperatmospheric or reduced pressures.

[0041] The order of the addition of the reaction components is inprinciple unimportant. For example, the hydroxy aromatic compound can beinitially taken as such or in solution, the catalyst as such, as anadduct or as a mixture with an ether can be added and finally thepolyolefin, likewise as such or in solution, can be added.Alternatively, the hydroxy aromatic compound can also be initially takentogether with the polyolefin, and the Lewis acid added. The reaction canbe stopped by means of a base, for example ammonia solution. Afterwashing with water, the organic phase is generally dried by conventionalmethods, for example over sodium sulfate or magnesium sulfate, and thesolvent is removed.

[0042] Some particularly preferred reaction systems are mentioned below:

[0043] BF₃ and complexes

[0044] A polyisobutylene having a vinylidene content of less than 65%(e.g. less than 50%, 40%, 30%) is reacted with phenol, ortho-cresol orpara-cresol using BF₃ as a catalyst, with or without correspondingcocatalysts, to give polyisobutenylphenol or polyisobutenylcresol.Examples are the BF₃ complexes with phenol or ethers, such as (C₂H₅)₂O,(n-C₃H₇)₂O, (i-C₃H₇)₂O, t-C₄H₉—O—CH₃, t-C₄H₉—O-i-C₃H₇, tetrahydrofuran,dicyclohexyl ether or anisole.

[0045] SnCl₄, FeCl₃, TiCl₄ and their complexes

[0046] A homopolyisobutylene having a vinylidene content which is lessthan 65% (e.g. 30, 50 or 60%) is reacted with phenol, ortho-cresol orpara-cresol using SnCl₄, FeCl₃ or TiCl₄ as the Lewis acid catalyst, withor without corresponding cocatalysts to give polyisobutenylphenol orpolyisobutenylcresol. SnCl₄ complexes, FeCl₃ complexes and TiCl₄complexes with ethers such as (n-C₃H₇)₂O, (i-C₃H₇)₂O, t-C₄H₉—O—CH₃,t-C₄H₉—O-i-C₃H₇, tetrahydrofuran, dicyclohexyl ether or anisole, arepreferably used.

[0047] Complexes with ethers in a molecular weight range M from 102 to242, such as (n-C₃H₇)₂O, (i-C₃H₇)₂O, t-C₄H₉—O—CH₃, t-C₄H₉—O-i-C₃H₇,dicyclohexyl ether or anisole, should be particularly singled out. Ahomopolymer of isobutene which comprises at least 90% (e.g. 95%) ofisobutene units and which in total is α- or β-olefin terminated to anextent of at least 80% can be particularly uniformly reacted therewith.Thus, uniform 4-polyisobutenyl-phenols, 2-methyl-4-polyisobutenylphenolsor 4-methyl-2-polyiso-butenylphenols are obtained with only small excessamounts (e.g. 5 or 15%) of phenol, o-cresol or p-cresol. These containless than 20, generally less than 10 or 5, mol % of more highlysubstituted isomers, for example the disubstitution products. Largerexcess amounts of phenol or cresol are possible and lead to an evenhigher content of 4-isobutenylphenol (from phenol or ortho-cresol) or2-isobutenylphenol (from para-cresol) in the product.

[0048] When BF₃ and complexes thereof are used, the reaction ispreferably carried out at from −10 to 50° C. Alkylation can beparticularly easily effected at from 15 to 40° C. The reaction ispreferably carried out at from −10 to 100° C. in the case of SnCl₄ andFeCl₃ and complexes thereof, and at from −10 to 80° C. in the case ofTiCl₄ and complexes thereof. In these cases, alkylation can beparticularly easily effected at from 15 to 60° C.

[0049] The polyisobutenylphenols obtained by the novel process aresuitable for a large number of industrial applications and in particularas fuel additives and as intermediates for the preparation of fueldetergents.

[0050] The present invention furthermore relates to a process for thepreparation of functionalized polyisobutenylphenols, comprising:

[0051] i) the preparation of polyisobutenylphenols by alkylating anaromatic hydroxy compound with substantially monoethylenicallyunsaturated polyisobutenes in the presence of a Lewis acid alkylationcatalyst, as described above, and

[0052] ii) the functionalization of the polyisobutenylphenols obtainedin step i) by aminoalkylation and/or polyether formation.

[0053] Suitable processes for the preparation ofpolyisobutenylphenol-containing Mannich adducts are known to a personskilled in the art and are described, for example, in EP-A-0 831 141 andthe unpublished German patent application P 199 48 114.8, which arehereby incorporated by reference in the entirety.

[0054] The examples which follow illustrate the invention withoutrestricting it.

EXAMPLE 1

[0055] 24 g of phenol are melted under nitrogen at 40 to 45° C. in afour-necked flask. 3.5 g of BF₃ diethyl ether adduct are added and themixture is cooled to room temperature. Then 80 g of polyisobutene (Mn=1000, containing 60% of terminal dimethylvinyl groups and 35% of terminalmethylvinylidene groups), as a solution in 100 ml of hexane, are addeddropwise at from 20 to 25° C. and this mixture is stirred at atemperature of 30° C. for 4 h. The reaction is stopped with 100 ml of25% ammonia solution, the organic phase is washed with water and driedover Na₂SO₄, and the solvent is distilled off. This gives 39 g of an oil(polyisobutenylphenol).

[0056] NMR: 7.2 ppm (doublet, 2H), 6.7 ppm (doublet, 2H), 4.8 ppm(singlet, 1H), 1.75 ppm (singlet, 2H), 1.5−0.5 ppm (singlets, 139H)

[0057] This corresponds to an Mn of the alkyl radical of 1 000.

[0058] The NMR spectrum corresponds to that of a para-substitutedpolyisobutenylphenol. In the signal range from 7.1 to 6.75 ppm, thereare small signals which represent about 5% of 2- or 2,4-substitutedphenol.

EXAMPLE 2

[0059] 56.7 g of phenol are dissolved in 30 ml of xylene in afour-necked flask. 4.6 g of BF₃-phenol complex are added at atemperature of from 20 to 25° C. and 295 g of polyisobutene (Mn=950,containing 49% of terminal dimethylvinyl groups and 45% of terminalmethylvinylidene groups), in solution in 200 ml of hexane, are addeddropwise over the course of 15 minutes at a temperature in the rangefrom 20 to 30° C. The mixture is then reacted at a temperature of from20 to 25° C. for 18 h and the resulting solution is extracted 4 timeswith 130 ml of methanol each time. The solvent is removed at 120° C. and5 mbar, giving 290 g of a viscous pale oil.

[0060] GPC (gel permeation chromatography) indicated a number-averagemolecular weight Mn of 1 050 and a polydispersity PD of 1.5.

[0061] NMR: 7.2 ppm (doublet, 2H), 6.7 ppm (doublet, 2H), 4.8 ppm(singlet, 1H), 1.75 ppm (singlet, 2H), 1.5−0.5 ppm (singlets, 135H)

[0062] The NMR spectrum corresponds to that of a para-substitutedpolyisobutenylphenol. In the signal range from 7.1 to 6.75 ppm, thereare small signals which may represent about 5% of 2- or 2,4-substitutedphenol.

EXAMPLE 3

[0063] 10 g of phenol are dissolved in 10 ml of xylene in a 250 mlfour-necked flask. 3.2 g of BF₃-phenol complex are added at atemperature of from 20 to 25° C. 100 g of polyisobutene (Mn=1 050,containing 40% of terminal dimethylvinyl groups), in solution in 60 mlof kerosene, are added dropwise over the course of 15 minutes at 15° C.and the resulting mixture is left to react at a temperature of from 20to 25° C. for 4.5 h. The resulting solution is extracted 4 times with 50ml of methanol each time and then the solvent is removed at 120° C. and5 mbar, giving 105 g of a viscous pale oil.

[0064] NMR: 7.2 ppm (doublet, 2H), 6.7 ppm (doublet, 2H), 4.8 ppm(singlet, 1H), 1.75 ppm (singlet, 2H), 1.5−0.5 ppm (singlets, 135H)

[0065] The NMR spectrum corresponds to that of a para-substitutedpolyisobutenylphenol. In the signal range from 7.1 to 6.75 ppm, thereare small signals which may represent about 5% of 2- or 2,4-substitutedphenol.

EXAMPLE 4

[0066] 24 g of phenol are melted under nitrogen at from 40 to 45° C. ina four-necked flask. 3.5 g of BF₃ diethyl ether adduct are addeddropwise and the mixture is cooled to room temperature. 80 g ofpolyisobutene (Mn=1 000, containing 60% of terminal dimethylvinyl groupsand 32% of α-olefin), in solution in 100 ml of hexane are added dropwiseat from 20 to 25° C. Stirring is then continued at 30° C. for 4 h. Thereaction is stopped with 100 ml of 25% ammonia solution. The organicphase is washed with water, dried over Na₂SO₄ and concentrated in arotary evaporator:

[0067] 67 g of oil (PIB phenol)

[0068] NMR:

[0069] 7.2 ppm (doublet, 2H), 6.7 ppm (doublet, 2H), 4.8 ppm (singlet,1H), 1.75 ppm (singlet, 2H), 1.5−0.5 ppm (singlets, 139H)

[0070] This corresponds to an Mn of the alkyl radical of 1 000.

[0071] The NMR spectrum corresponds to that of a para-substitutedpolyisobutenylphenol. In the signal range from 7.1 to 6.75 ppm, thereare small signals which represent from 5 to 10% of 2- or 2,4-substitutedphenol.

EXAMPLE 5

[0072] 21 g of phenol are dissolved in 15 ml of xylene in a four-neckedflask. 5 g of BF₃-phenol complex are added at a temperature of from 20to 25° C. 120 g of polyisobutene (Mn=550, containing 40% of β-olefin and54% of α-olefin) in solution in 60 ml of kerosene are added dropwiseover the course of 30 minutes at a temperature of from 20 to 25° C. andthe resulting mixture is then left to react at a temperature of 25° C.for 4 h. The resulting solution is extracted 3 times with 130 ml ofmethanol each time and the solvent is removed on a rotary evaporator at120° C. and 5 mbar, giving 125 g of a pale viscous oil.

[0073] NMR:

[0074] 7.2 ppm (doublet, 2H), 6.7 ppm (doublet, 2H), 4.8 ppm (singlet,1H), 1.75 ppm (singlet, 2H), 1.5−0.5 ppm (singlets, 77H)

[0075] The NMR spectrum corresponds to that of a para-substitutedpolyisobutenylphenol. In the signal range from 7.1 to 6.75 ppm, thereare small signals which represent about 10% of 2- or 2,4-substitutedphenol.

EXAMPLE 6

[0076] 10 g of phenol are dissolved in 10 ml of toluene in a 250 mlfour-necked flask. 5 g of BF₃ phenoxide and 4 g of diisopropyl ether areadded at a temperature of from 20 to 25° C. 100 g of polyisobutene(Mn=990, containing 53% of β-olefin and 44% of α-olefin) in solution in60 ml of kerosene, are added dropwise over 30 minutes at from 20 to 25°C. and the resulting mixture is left to react at a temperature of 25° C.for 8 h. The resulting solution is extracted 3 times with 130 ml ofmethanol each time and then the solvent is removed on a rotaryevaporator at 120° C. and 5 mbar, giving 100 g of a viscous pale oil.

[0077] NMR: 7.2 ppm (doublet, 2H), 6.7 ppm (doublet, 2H), 4.8 ppm(singlet, 1H), 1.75 ppm (singlet, 2H), 1.5−0.5 ppm (singlets, 142H)

[0078] The NMR spectrum corresponds to that of a para-substitutedpolyisobutenylphenol. In the signal range from 7.1 to 6.75 ppm, thereare small signals which represent from 5 to 10% of 2- or 2,4-substitutedphenol.

We claim:—
 1. A process for the preparation of polyisobutenylphenols byalkylating an aromatic hydroxy compound with substantiallymonoethylenically unsaturated and substantially homopolymericpolyisobutenes in the presence of a Lewis acid alkylation catalyst,wherein the polyisobutenes have a β double bond content of at least 35mol %.
 2. A process as claimed in claim 1, wherein additionally an etheris used as cocatalyst.
 3. A process as claimed in either of claims 1 or2, wherein the catalyst is selected from the halides of boron, aluminum,tin or a transition metal.
 4. A process as claimed in claim 3, whereinthe catalyst is selected from BF₃, SnCl₄, TiCl₄ and FeCl₃.
 5. A processas claimed in any of the preceding claims, wherein the ether has amolecular weight of from 102 to 242 g/mol.
 6. A process as claimed inany of the preceding claims, wherein catalyst and cocatalyst are used ina molar ratio of from 1:10 to 10:1.
 7. A process as claimed in any ofthe preceding claims, wherein aromatic hydroxy compounds andpolyalkylenes are used in a molar ratio of from 1.5:1 to 1:1, preferablyfrom 1.2:1 to 1:1.
 8. A process as claimed in any of the precedingclaims, wherein the polyisobutenylphenols obtained are polyalkylatedwith the polyisobutene to a degree of not more than 20, preferably notmore than 10, in particular not more than 5, mol %.
 9. A process asclaimed in any of the preceding claims, wherein from 1 to 30 mol %,based on the polyolefin, of catalyst or catalyst/cocatalyst complex areused.
 10. A process as claimed in any of the preceding claims, whereinthe alkylation is effected at from 15 to 40° C.
 11. A process as claimedin any of the preceding claims, additionally comprising thefunctionalization of polyisobutenylphenols by aminoalkylation and/orpolyether formation.